Bus systems are increasingly used in place of wiring harnesses for connecting different components or devices, respectively in a motor vehicle. A plurality of components are typically coupled to one another in what is known as a ring bus. The individual components connected to one another in ring form exchange their data with one another via wire conductors or optical fibers. A diagnostics interface is provided in a typical ring bus to allow routine tests to be carried out, such as to check the functions of the components as well as to search for a defective component in an optical ring bus. During normal operation a bridging plug is inserted in this interface to bridge or short-circuit the interface and, thereby complete the ring of the ring bus. The bridging plug is removed for diagnostic purposes, making the diagnostics interface accessible for coupling to a diagnostic or test device.
Generic optical short-circuit plugs are described for example in DE 35 44 137 A1, in U.S. Pat. No. 4,982,083 A and in U.S. Pat. No. 5,076,688 A. An optical short-circuit plug provided in DE 44 28 855 A1 for short-circuiting two optical units contains a short-circuit optical fiber whose ends are each received by a contact pin for coupling to the optical units. The contact pins are provided as separate elements and are enveloped in a sleeve of elastic material. The sleeve deforms during pin mounting to generate a defined application force and for tolerance compensation.
Finally an optical connector plug is provided by DE 199 51 257 A1 for bridging an open or non-assigned or interrupted plug connection in an optical bus system. The optical connector plug has a plug housing with a plug region by means of which the connector plug can be plugged onto the plug end. A groove is molded into the plug housing into which groove an optical fiber with attached fiber end sleeves is laid.
However, a need still exists for a compact optical short-circuit insert and a corresponding short-circuit plug. This object is achieved by the present invention, as will be described hereafter.